Premium
Optokinetic stimulation increases limb pain and forehead hyperalgesia in complex regional pain syndrome
Author(s) -
Knudsen L.F.,
Drummond P.D.
Publication year - 2015
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1002/ejp.602
Subject(s) - hyperalgesia , forehead , sensory system , medicine , complex regional pain syndrome , nociception , physical medicine and rehabilitation , allodynia , psychology , anesthesia , neuroscience , surgery , receptor
Background Ambiguous visual stimuli increase limb pain in patients with complex regional pain syndrome ( CRPS ), possibly due to afferent sensory feedback conflicts. Conflicting sensory stimuli can also generate unpleasant sensations in healthy people such as during motion sickness. We wanted to investigate the mechanisms underlying the link between sensory conflicts and pain in CRPS using optokinetic stimulation ( OKS ) – a method known to induce motion sickness. Methods Twenty‐one CRPS patients underwent OKS and rated symptoms of motion sickness. Patients also rated limb pain and pain‐related distress before, during and after OKS . In addition, pressure‐pain and sharpness sensations were investigated on both sides of the forehead and in the affected and contralateral limb before and after OKS . Results Limb pain and forehead hyperalgesia to pressure increased in parallel in response to OKS . In a subgroup of nauseated patients who withdrew early from OKS , hyperalgesia to pressure in the ipsilateral forehead persisted longer than in the remaining participants. Sharpness sensations remained constant at all sites. Conclusions Sensory conflicts may facilitate pain in CRPS by activating the mechanisms of general facilitation of nociception and, during more severe sensory conflicts, also a facilitatory mechanism that operates mainly ipsilateral to the affected limb.